The aquarium's stated vision is to confront pressing issues facing global aquatic habitats through pioneering science, conservation, and educational programming.

"[7] The aquarium opened a marine mammal pavilion on the adjacent south end of Pier 4 in 1990, and currently holds six Atlantic bottlenose dolphins.

[16] Some of the center's projects include "The Chesapeake Bay Initiative", tracking mercury levels through the food chain in wild and captive bottlenose dolphins, and assessing chronic natural resource damages from the BP oil spill in the Gulf of Mexico.

[16] In 2011, The National Aquarium was honored with the Maryland Green Registry Leadership Award, as an organization that shows “a strong commitment to sustainable practices, measurable results, and continuous improvement” [17] and was recognized by the Baltimore Business Journal and Smart CEO Magazine for exceptional green business practices in 2009.

[18] A 4.3 MW solar farm in Cambridge supplies about 40% of the power for the National Aquarium, and saves about 1,300 metric tons of carbon dioxide during the summer.

Originally, it was a marine mammal exhibit that had bottlenose dolphins collected from the Gulf of Mexico and eventually, California Sea Lions and beluga whales, but when Pier 4 opened, the animals were moved there.

On the exit side of Blacktip Reef, an entire guest walkway was cut back considerably to create the sandbar section of the exhibit.

This 265,000-US-gallon (1,000,000 L) habitat, replicating an Indo-Pacific reef landscape (living corals are exhibited elsewhere in the National Aquarium), can be seen from many vantage points, including a new floor-to-ceiling pop-out viewing window.

[22] In October 2020, the National Aquarium announced its acquisition of another green sea turtle, Kai, who had suffered injuries in a collision with a boat that left her unable to dive for food.

The four exhibits create the illusion that the viewer is traveling down a Maryland stream from its source in the Allegheny Mountains, to a tidal marsh, to a coastal beach, and finally ending at the Atlantic shelf.

Featured animals include wood turtle, American bullfrog, and rosyside dace in the Allegheny Stream, diamondback terrapin, striped blenny, and sheepshead minnow in the Tidal Marsh, striped burrfish and lookdown in the Coastal Beach, and clearnose skate and summer flounder in the Atlantic Shelf exhibit.

Featured animals include electric eel, lined seahorse, longnose gar, peacock mantis shrimp and Spotfin butterflyfish.

Featured animals include: This large 335,000-US-gallon (1,270,000 L) exhibit replicates the Atlantic coral reef, and is filled with more than 100 exotic species that would be found anywhere from closer to shore to out into the trench and open ocean, including a green moray eel, queen triggerfish, black grouper, blacknose shark, southern stingray, Atlantic tarpon, spotfin butterflyfish, spot-fin porcupinefish, and a Kemp's ridley sea turtle.

[25] This smaller building, opened in December 1990, features the marine mammal exhibit, which is home to Atlantic bottlenose dolphins in a 1,300,000-US-gallon (4,900,000 L) facility.

[26] In June 2016, the National Aquarium announced plans to construct a sanctuary in Florida or the Caribbean for its colony of bottlenose dolphins.

[28] As of late 2023, the Aquarium had narrowed down potential locations for the sanctuary to either the U.S. Virgin Islands or Puerto Rico, and planned to relocate the dolphins there by 2026.

Other parts of this plan include the creation of a "wetland" in between the two buildings and the transformation of Pier 3 into a collection of "hope spots" bringing the aquarium to 360,000 sq ft (33,000 m2) of space in total.

Guests can see more than 1,800 individual native animals including freshwater crocodiles, turtles, free-flying birds, snakes, and lizards.

Founded in 1873, it originally was distinct from the later National Aquarium in Baltimore, opened 108 years later and 40 miles (64 km) to the northeast of Washington.

A signing ceremony formally recognizing the alliance hosted by United States Secretary of Commerce Donald Evans took place at the Herbert C. Hoover Building.

Details regarding funding, staffing, and programming are made available to the public within each year's annual report downloadable on the National Aquarium Institute's website.

"[38] In September 2011, the City Paper Reader's Poll awarded the National Aquarium with the title of "Best Attraction" and the "Best Place to Take Kids".